Peroxygen bleach-containing compositions have been extensively described in laundry applications as laundry detergents, laundry additives or even laundry pretreaters.
Indeed, it is known to use such peroxygen bleach-containing compositions in laundry pretreatment applications to boost the removal of encrusted stains/soils which are otherwise particularly difficult to remove such as grease, coffee, tea, grass, mud/clay-containing soils and the like. However, we have found that a drawback associated with such peroxygen bleach-containing compositions is that said compositions may damage fabrics when used in pretreatment application, i.e. when applied directly onto the fabrics, and left to act onto said fabrics for prolonged periods of time before washing said fabrics.
It is thus an object of the present invention to provide improved fabrics safety when pretreating fabrics with peroxygen bleach-containing compositions, especially in those applications where said compositions are left into contact with said fabrics during prolonged periods of time, before washing said fabrics.
When pretreating fabrics with compositions comprising a peroxygen bleach like hydrogen peroxide, it has been found that the presence of metal ions such as copper and/or iron and/or manganese on the surface of fabrics produces fabric damage resulting in loss of tensile strength of the fabric fibres. It is speculated that the presence of metal ions such as copper and/or iron and/or manganese on the surface of the fabrics, especially on cellulosic fibres, catalyses the radical decomposition of peroxygen bleaches like hydrogen peroxide. Thus, a radical reaction occurs on the surface of the fabric with generation of free radicals, which results in tensile strength loss.
Therefore we have found that it is essential that this surface radical reaction be controlled in the pretreatment environment, thereby providing improved safety to fabrics.
It has now been found that this can be achieved by formulating a peroxygen bleach-containing composition which comprises a compound for chelating copper and/or iron and/or manganese. More particularly, it has been found that the use of a compound for chelating copper and/or iron and/or manganese, and preferably diethylene triamine penta methylene phosphonic acid (DTPMP), hydroxy-ethane diphosphonic acid (HEDP), ethylenediamine N,N'-disuccinic acid (EDDS), methyl glycine di-acetic acid (MGDA), diethylene triamine penta acetic acid (DTPA), propylene diamine tetracetic acid (PDTA), 2-hydroxypyridine-N-oxide (HPNO), or ethylenedinitrilotertrakis (methylenephosphonic acid) N,N,-dioxide, in a peroxygen bleach-containitng composition, considerably reduces the damage on a fabric pretreated with such a composition.
An advantage associated to the use of a peroxygen bleach-containing composition comprising such a compound for chelating copper and/or iron and/or manganese, in laundry pretreatment application, is that color damage is also reduced.
A further advantage of the present invention is that excellent laundry performance on bleachable stains is provided as well as on removing greasy stains.
Another advantage of the present invention is that the compositions suitable to be used according to the present invention also provide excellent performance when used in other applications, apart from laundry pretreater application, such as in other laundry applications, as a laundry detergent or laundry additive, or even in hard surface cleaning applications.
In one embodiment of the present invention it has also been found that the use of a chelating agent like ethylenedinitrilotertrakis (methylenephosphonic acid) N,N,-dioxide, hydroxy-ethane diphosphonic acid (HEDP) and/or a chelating agent having two electron-donor groups able to occupy adjacent co-ordination sites in the metal ions sphere of co-ordination so as to form complexes with metal ions in which each metal ion is complexed by 3 molecules of chelating agents like 2-hydroxypyridine-N-oxide, allows to formulate acidic liquid compositions suitable for pretreating fabrics which exhibit improved chemical stability upon prolonged storage time.
Peroxygen bleach-containing compositions have been extensively described in the art. EP-A- 629691 discloses emulsions of nonionic surfactants comprising a silicone compound, and as optional ingredients, hydrogen peroxide, or a water soluble source thereof, and chelants. The only chelant disclosed is S,S,-ethylene diamino disuccinic acid (see examples). Although pretreatment application is disclosed for the compositions of EP-A 629691, the use of peroxygen bleach-containing compositions comprising a compound chelating copper and/or iron and/or manganese, for pretreating fabrics, whereby the loss of tensile strength in said fabrics is reduced, is nowhere disclosed.
EP-A- 629690 discloses emulsions of nonionic surfactants comprising a terephthalate-based polymer, and as optional ingredients, hydrogen peroxide, or a water soluble source thereof, and chelants. The only chelant disclosed is S,S,-ethylene diamino disuccinic acid (see examples). Although pretreatment application is disclosed for the compositions of EP-A 629690, the use of peroxygen bleach-containing compositions comprising a compound chelating copper and/or iron and/or manganese, for pretreating fabrics, whereby the loss of tensile strength in said fabrics is reduced, is nowhere disclosed.
EP-B-209 228 discloses compositions comprising a peroxide source like hydrogen peroxide, an amino polyphosphonate chelant and a radical scavenger. Diethylene triamine penta methylene phosphonic acid is expressly disclosed. Also EP-B-209 228 discloses that the hydrogen peroxide-containing compositions may be used as pre-spotters. However, nowhere it is mentioned that peroxygen bleach-containing compositions comprising a compound chelating copper and/or iron and/or manganese, for pretreating fabrics, allow to reduce the loss of tensile strength in said fabrics.